Various solutions exist wherein a reader device is used to read different identifiers that are separate from the reader device. In some solutions the reader device is configured to read an identifier that is separate from the reader device and is provided with a readable marking when the identifier is situated within range of the reading signal of the reader device. In some solutions RFID identifiers are read with a reader device. In this case the reader device usually comprises an antenna, by the aid of which the reader device forms a wirelessly propagating electromagnetic reading signal. The identifier to be read in this case also comprises an antenna, and communication between the reader device and the identifier occurs via the aforementioned electromagnetic reading signal. Communication occurring via an electromagnetic field can be based on either the near-field or far-field principle.
In some solutions the identifier also receives the operating electricity it needs from the reading signal, when the identifier is situated within range of the reading signal.
The solutions described above can be used e.g. for identifying an elevator passenger. If the elevator passenger carries along with him/her the aforementioned type of identifier, the elevator passenger who has arrived/is arriving in the building can be identified by reading the marking in the identifier. Identification can occur automatically when an elevator passenger arrives within range of the reading signal of a reader device disposed in the building; in some cases the elevator passenger must also separately hold out the identifier so that it is sufficiently close to the reader device. On the basis of the identification, the control system of the elevator can form an elevator call, which includes default data about the destination floor that is the destination of the identified elevator passenger. If reading of the identifier/identification of the elevator passenger occurs already before the elevator passenger has gone into the elevator car, the elevator call can be allocated for serving to the elevator car best suited for the purpose using in the allocation data about both the departure floor and the destination floor of the elevator passenger. This type of system is advantageous from the viewpoint of an elevator passenger, because it reduces the need for conventional elevator calls given by hand. Also the transport capacity of the elevator system improves.
Failure of a reader device in the aforementioned solutions would result in elevator passengers failing to be identified, in which case elevator calls would have to be given manually with separate call-giving devices. Also the allocation of elevator calls would become more difficult if information about the identification data of elevator passengers was not available.
The aforementioned combination of reader device/identifiers can also be used e.g. for determining the location of an elevator car. One such solution is described in international patent application WO 2010/018298 A1, in which described solution a reader device is fitted in connection with an elevator car and identifiers are disposed in the elevator hoistway beside the path of movement of the elevator car. The position of the stopping floors of an elevator car moving in the elevator hoistway is determined by reading the identifiers fitted beside the path of movement of the elevator car with the reader device fitted in connection with an elevator car. The elevator car is situated at the point of a stopping floor when the identifier is situated within range of the reading signal of the reader device moving along with the elevator car. In the aforementioned solution, the identifiers disposed in the elevator hoistway can also be used to determine the extreme limits of the permitted movement of the elevator car in the elevator hoistway. When the reader device fails, determination of the location of the elevator car no longer succeeds, in which case the elevator car might drive past a stopping floor or move outside the range of permitted movement of the elevator car.
One problem relating to the aforementioned solutions is that detecting failure of a reader device is difficult and repairing a defect is slow, because it can occur only on the basis of feedback received from a user of the elevator or as a consequence of a failure of the control system of the elevator. Failure of the control system of an elevator additionally results in an interruption in the operation of the elevator.
Therefore a need to develop monitoring of the condition of a reader device exists.